Austrian Journal of Technical and
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Scopus, Web of ScienceAustriya-11-12,2019 (2) - копия
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- Subjects and methods.
Key words: Mo concentrate, cinder, kaolin, organic polymer, granulation.
Introduction. Technology of production of the pyrite cinders of molybdenum middlings at JSC “Almalyk GMK” [1] includes the steps of: mixture granulation (composition: Mo-concentrate 90%, kaolin 10%), firing of pellets at 600 °C to oxidize sulfide minerals and to recover rhenium oxide. As a result of the dilution of the original Mo concentrate with kaolin there is a “dilution” of the pyrite cinders upon molybdenum. In this context, the search of pellet-forming scheme that minimizes this rate is the actual problem. The data revealed that if we use Objective: To provide such a binder for JSC “Almalyk GMK”. Its requirements: it should not contain any “technological poisons” (such as phosphates) adversely affecting the redistribution of cinder: leaching, sorption of Mo (VI) ions, hydrogen reduction to metal, sintering rods. Tasks: to compare the hydrophilic, strength and technological properties of binders: kaolin and alternatives to it of organic and organic-mineral nature, being in the composition of pellets and cinder of Mo concentrate. Subjects and methods. Batch of Mo concentrate ranulation was prepared using 11-12, 2019 42 the traditional composition of the batch mixture in the production of cider, the proportion of Mo in the granules is reduced to 4%. In addition, it is known that the presence of kaolin in cinder makes difficult to sublimate rhenium oxide and impairs its commodity indices such as the fullness of ammonia leaching, Au and Ag extraction from a cake. To improve these technical and economic indicators was an idea to replace, completely or partially, kaolin with organic binder to be burned at a sintering of Mo- concentrate and causing no dilution of the product. Limiting wetting angles of the batches prepared on Moconcentrate base in compare with few reference data [6] are offered in From Table 1 it is revealed that the sample Nr 1 is identified as being hydrophobic material. Decrease of its hydrophobicity was facilitated with binders allowing it to be granulated. Selection of the best of them for the role of alternative to kaolin was intended to experiment aimed at a comparison between the strength of granules with a diameter of 3–5 mm, made of MoS2-containing batch materials with binders, after their dryingfiring at 20, 250, 600 °C. (Tabletka). In manufacture of candle end of Mo middlings the requirement to the durability of granules is empirically revealed, adjustable by a mode of balling in dish nodulizer of own design, with diameter of a plate made of a stainless steel equal to 2 m, as well as by batch composition,%: Мо-concentrate 92–90, kaolin 8–10. The corner of an inclination of a dish, speed of its rotation and submission of a batch with water, time of balling were selected too empirically, aspiring to the optimum size and durability of the granules. At understating of the kaolin maintenance in granule’s batch mixes their resistance to abrasive wear on a way to a furnace fell, at their overestimate — permeability of oxygen in granules (О2 is necessary for oxidation of molybdenite up to trioxide of Мо) was blocked: in both cases the content of sulfur in the candle end exceeded norm of State standard 2677–78.So one of the research’s problems was the quantitative description of the above- stated requirement empirically revealed by the industry to durability of bindering: kaolin, bentonite, liquid glass LG, Na-carboxymethylcellulose (NaCMC), polyvinyl acetate (PVA), sulfonated cellulose [2;3], hydrolysis product of waste of production of polyacrylonitrile fiber SC. Their composition (binder content,%; Mo I (J,%) was determined as a percentage of reflex expressed at the maximum. Results and discussions. The Mo concentrate’s composition supplied to the granulating was the following, %: Mo 38; Re 0.7; Cu 2.5; P 0.009; Sb 0.025; WO3 0.05;S 25.2; SiO2 10.8; humidity 0.42; peculiar to Mo concentrate quantities of Au and Ag presented there too. 7 (bentonite 2%, PVA 2%), 8 (bentonite 2%, sulfonated cellulose 2%). 9 (SC 1%), 10 (SK 1.5%, LG 1.5%),11 (bentonite 2%, SC 1.5%, LG 1.5%), 12 (kaolin 2%, SC 1.5%; LG 1.5%), 13 (LG 3%); 14 (bentonite 2%,CMC 1.5%); 15 (bentonite 2%, SC 0.5%); 16 (kaolin 2%, SC 0.5%); 17 (bentonite 1%, CMC 0.5%), 18 (bentonite 1%, SC 0.5%). Limiting wetting angle of batch material compacted under a pressure of 20 MPa ( ∅ 12, height: 4 mm) wasdetermined from the profile of water droplets thereon [4]. The granules were obtained in the disc pelletizer, then dried at 20 °C, 24 hr. Their crushing strength was evaluated with the following methods: 1) of integrity of the granules dropped from a height of 2 m onto concrete; 2) of compression fracture. Their comparison revealed allowable strength criterion: F ≥ 1.2 MPa. The content of elements in the raw materials and technological solutions was determined by ultimate analysis carried by AAS "Perkin- Elmer" PE 3030V with a flaming atomizer, and Aligent 7500 ICP MS. Thus, Au and Ag in the samples were determined at wavelengths of 242.8 and 328.1 nm with preconcentration extraction in a toluene solution of sulfide oil at a ratio of organic / aqueous phases = 1/10, respectively. IR absorption spectra were recorded in the range of 400-4000 cm-1 with AVATAR-360 spectrometer Nico let. Thermograms were recorded by derivatograph Paulik Erdey at gradient 10 degrees per min, sample weight 0.200-0.250 g, in corundum crucible ∅ 10 mm, with T-900, TG-200, the DTA-1/10, DTG1/20 sensitive galvanometers and Al2O3 as a |
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